Method and system for automatically tracking the rerouting of logical circuit data in a data network

ABSTRACT

A method and system are provided for tracking the rerouting of logical circuit data in a data network. A disclosed example method involves updating reroute information in response to a dropped packet associated with a quality of service parameter having been exceeded. Transmitted data is rerouted to at least one logical failover circuit in the data network from at least one failed logical circuit associated with the exceeded quality of service parameter. The at least one logical failover circuit is selected based on a bit rate capability specified to be one of a committed bit rate, a variable bit rate, or an unspecified bit rate.

PRIORITY APPLICATIONS

This patent is a continuation of U.S. patent application Ser. No.10/829,584, filed Apr. 22, 2004, which is hereby incorporated herein byreference in its entirety.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent is related to U.S. patent application Ser. No. 10/348,077,entitled “Method and System for Obtaining Logical Performance Data for aCircuit in a Data Network,” filed Jan. 21, 2003, and U.S. patentapplication Ser. No. 10/348,592, entitled “Method and System forProvisioning and Maintaining a Circuit in a Data Network,” filed Jan.21, 2003. This application is also related to U.S. patent applicationSer. No. 10/745,117, entitled “Method And System For Providing AFailover Circuit For Rerouting Logical Circuit Data In A Data Network,”filed Dec. 23, 2003, U.S. patent application Ser. No. 10/745,047,entitled “Method And System For Automatically Renaming Logical CircuitIdentifiers For Rerouted Logical Circuits In A Data Network,” filed Dec.23, 2003, U.S. patent application Ser. No. 10/745,170, entitled “MethodAnd System For Automatically Identifying A Logical Circuit Failure In AData Network,” filed on Dec. 23, 2003, and U.S. patent application Ser.No. 10/744,921, entitled “Method And System For Automatically ReroutingLogical Circuit Data In A Data Network,” filed Dec. 23, 2003. All of theabove-referenced applications are expressly incorporated herein byreference.

FIELD OF THE DISCLOSURE

The present invention relates to the routing of data using logicalcircuits in a data network. More particularly, the present invention isrelated to automatically tracking the rerouting of logical circuit datain a data network.

BACKGROUND OF THE INVENTION

Data networks contain various network devices, such as switches, forsending and receiving data between two locations. For example, framerelay and Asynchronous Transfer Mode (“ATM”) networks containinterconnected network devices that allow data packets or cells to bechanneled over a circuit through the network from a host device to aremote device. For a given network circuit, the data from a host deviceis delivered to the network through a physical circuit such as a T1 linethat links to a switch of the network. The remote device thatcommunicates with the host through the network also has a physicalcircuit to a switch of the network. A network circuit also includes alogical circuit which includes a variable communication path for databetween the switches associated with the host and the remote device.

In large-scale networks, the host and remote end devices of a networkcircuit may be connected across different local access and transportareas (“LATAs”) which may in turn be connected to one or moreInter-Exchange Carriers (“IEC”) for transporting data between the LATAs.These connections are made through physical trunk circuits utilizingfixed logical connections known as Network-to-Network Interfaces(“NNIs”).

Periodically, failures may occur to the trunk circuits or the NNIs ofnetwork circuits in large-scale networks causing lost data. Currently,such network circuit failures are handled by dispatching technicians oneach end of the network circuit (i.e., in each LATA) in response to areported failure. The technicians manually access a logical elementmodule to troubleshoot the logical circuit portion of the networkcircuit. The logical element module communicates with the switches inthe data network and provides the technician with the status of thelogical connections which make up the logical circuit. Once thetechnician determines the status of a logical connection at one end of alogical circuit (e.g., the host end), the technician then must access anetwork database to determine the location of the other end of thelogical circuit so that its status may also be ascertained. If thetechnician determines the logical circuit is operating properly, thetechnician then accesses a physical element module to troubleshoot thephysical circuit portion of the network circuit to determine the causeof the failure and then repair it. If, while troubleshooting a networkcircuit, the technician determines that a network circuit will be “down”(i.e., losing data) for an extended time period while troubleshooting anetwork circuit, the technician may manually reroute the data from afailed network circuit to an available unused or “backup” networkcircuit while the failed network circuit is being repaired.

Current methods of repairing network circuits, however, do not includetracking of rerouted network circuits. For example, while repairing anetwork circuit, data may be rerouted to a backup circuit having anidentification which is different than the original network circuitwhich failed. In order to access this information, a technician would berequired to manually access the network database to lookup theidentification of the failed network circuit and cross-reference thisinformation with data obtained from the logical element module toidentify the backup circuit used for rerouting network circuit data.Moreover, there is currently no way to monitor or track the performanceof backup network circuits over time such that underperforming orover-utilized backup circuits may be identified.

It is with respect to these considerations and others that the presentinvention has been made.

SUMMARY OF THE INVENTION

In accordance with the present invention, the above and other problemsare solved by a method and system for automatically tracking thererouting of logical circuit data in a data network. One method includesgenerating current reroute statistics upon the rerouting of logicalcircuit data from one or more failed logical circuits to one or morelogical failover circuits in the data network. The current reroutestatistics include trap data received for the one or more failed logicalcircuits in the data network. The method further includes generating atable for presenting the current reroute statistics without manualintervention and generating updated rerouted statistics which includeupdated trap data received for the one or more failed logical circuitsin the data network. The method further includes updating the table withthe updated reroute statistics without manual intervention.

The above-described method may further include generating a billingreport including the updated reroute statistics. The updated reroutestatistics may be generated upon the restoration of the one or morefailed logical circuits in the data network. Each of the one or morefailed logical circuits and each of the one or more logical failovercircuits in the data network may be identified by a logical circuitidentifier. The trap data may include the logical identifier for each ofthe one or more failed logical circuits and the logical identifier foreach of the one or more logical failover circuits. The trap data mayfurther include a current utilization of each of the one or more logicalfailover circuits. The trap data may further include the number of hopstaken by data in each of the one or more logical failover circuits. Thetrap data may further include quality of service parameters for each ofthe one or more logical failover circuits. The quality of serviceparameters may include an unspecified bit rate, a variable bit rate, anda committed bit rate.

The logical circuit identifiers may be data link connection identifiers(“DLCIs”) or virtual path/virtual circuit identifiers (“VPI/VCIs”). Thelogical circuits may be either permanent virtual circuits (“PVCs”) orswitched virtual circuits (“SVCs”). The data network may be either aframe relay network or an asynchronous transfer mode (“ATM”) network.

In accordance with other aspects, the present invention relates to asystem for automatically tracking the rerouting of logical circuit datain a data network. The system includes one or more network devices forrerouting logical circuit data between one or more failed logicalcircuits to one or more logical failover circuits in the data network, alogical element module, in communication with network devices, forreceiving trap data generated by network devices, and a networkmanagement module in communication with the logical element module. Thenetwork management module is utilized for generating current reroutestatistics upon the rerouting of logical circuit data from the one ormore failed logical circuits to the one or more logical failovercircuits. The current reroute statistics include the trap data receivedby the logical element module. The network management module is furtherutilized for generating a table for presenting the current reroutestatistics without manual intervention and generating updated reroutestatistics. The updated reroute statistics include the trap datareceived from the logical element module. The network management moduleis further utilized for updating the table with the updated reroutestatistics without manual intervention.

The network management module may be further operative to generate abilling report including the updated trap data. The updated trap datamay be generated upon the restoration of the one or more failed logicalcircuits in the data network. Each of the one or more failed logicalcircuits and each of the one or more logical failover circuits in thedata network may be identified by a logical circuit identifier. The trapdata may include the logical identifier for each of the one or morefailed logical circuits and the logical identifier for each of the oneor more logical failover circuits. The trap data may include a currentutilization of each of the one or more logical failover circuits. Thetrap data may include the number of hops taken by each of the one ormore logical failover circuits. The trap data may include quality ofservice parameters for each of the one or more logical failovercircuits. The quality of service parameters may include an unspecifiedbit rate, a variable bit rate, and a committed bit rate. The logicalcircuit identifiers may be data link connection identifiers (“DLCIs”) orvirtual path/virtual circuit identifiers (“VPI/VCIs”).

These and various other features as well as advantages, whichcharacterize the present invention, will be apparent from a reading ofthe following detailed description and a review of the associateddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a data network according to an embodiment of theinvention.

FIG. 2 illustrates a local access and transport area (“LATA”) in thedata network of FIG. 1, according to an embodiment of the invention.

FIG. 3 illustrates a network management system which may be utilized toautomatically rename logical circuit identifiers for rerouted logicalcircuits in the data network of FIG. 1, according to an embodiment ofthe invention.

FIG. 4 illustrates a failover data network for rerouting logical circuitdata, according to an embodiment of the invention.

FIG. 5 is a flowchart describing logical operations performed by thenetwork management system for automatically tracking the rerouting oflogical circuit data in the data network of FIG. 1, according to anembodiment of the invention.

FIG. 6A is a table presenting current reroute statistics which may begenerated by the network management module of FIG. 3 in the data networkof FIG. 1, according to an embodiment of the invention.

FIG. 6B is a table presenting updated reroute statistics which may begenerated by the network management module of FIG. 3 in the data networkof FIG. 1, according to an embodiment of the invention.

Embodiments of the present invention provide for a method and system forautomatically tracking the rerouting of logical circuit data in a datanetwork. In the following detailed description, references are made tothe accompanying drawings that form a part hereof, and in which areshown by way of illustration specific embodiments or examples. Referringnow to the drawings, in which like numerals represent like elementsthrough the several figures, aspects of the present invention and theexemplary operating environment will be described.

Embodiments of the present invention may be generally employed in a datanetwork 2 as shown in FIG. 1. The data network 2 includes local accessand transport areas (“LATAs”) 5 and 15 which are connected by anInter-Exchange Carrier (“IEC”) 10. It should be understood that theLATAs 5 and 15 may be data networks operated by a commonly owned LocalExchange Carrier (“LEC”). It should be further understood that the IEC10 may include one or more data networks which may be operated by acommonly owned IEC. It will be appreciated by those skilled in the artthat the data network 2 may be a frame relay network, asynchronoustransfer mode (“ATM”) network, or any other network capable ofcommunicating data conforming to Layers 2-4 of the Open SystemsInterconnection (“OSI”) model developed by the International StandardsOrganization, incorporated herein by reference. It will be appreciatedthat these networks may include, but are not limited to, communicationsprotocols conforming to the Multiprotocol Label Switching Standard(“MPLS”) networks and the Transmission Control Protocol/InternetProtocol (“TCP/IP”), which are known to those skilled in the art.

The data network 2 includes a network circuit which channels databetween a host device 112 and a remote device 114 through the LATA 5,the IEC 10, and the LATA 15. It will be appreciated by those skilled inthe art that the host and remote devices 112 and 114 may be local areanetwork (“LAN”) routers, LAN bridges, hosts, front end processors, FrameRelay Access Devices (“FRADs”), or any other device with a frame relay,ATM, or network interface. It will be further appreciated that in thedata network 2, the LATAs 5 and 15 and the IEC 10 may include networkelements (not shown) which support interworking to enable communicationsbetween host and remote devices supporting dissimilar protocols. Networkelements in a data network supporting interworking may translate framerelay data packets or frames sent from a host FRAD to ATM data packetsor cells so that a host device may communicate with a remote devicehaving an ATM interface. The LATAs 5 and 15 and the IEC 10 may furtherinclude one or more interconnected network elements, such as switches(not shown), for transmitting data. An illustrative LEC data networkwill be discussed in greater detail in the description of FIG. 2 below.

The network circuit between the host device 112 and the remote device114 in the data network 2 includes a physical circuit and a logicalcircuit. As used in the foregoing description and the appended claims, aphysical circuit is defined as the physical path that connects the endpoint of a network circuit to a network device. For example, thephysical circuit of the network circuit between the host device 112 andthe remote device 114 includes the physical connection 121 between thehost device 112 and the LATA 5, the physical connection 106 between theLATA 5 and the IEC 10, the physical connection 108 between the IEC 10and the LATA 15, and the physical connection 123 between the LATA 15 andthe remote device 114. Routers and switches within the LATAs 5 and 15and the IEC 10 carry the physical signal between the host and remote enddevices 112 and 114 through the physical circuit.

It should be understood that the host and remote devices may beconnected to the physical circuit described above using user-to-networkinterfaces (“UNIs”). As is known to those skilled in the art, an UNI isthe physical demarcation point between a user device (e.g, a hostdevice) and a public data network. It will further be understood bythose skilled in the art that the physical connections 106 and 108 mayinclude trunk circuits for carrying the data between the LATAs 5 and 15and the IEC 10. It will be further understood by those skilled in theart that the connections 121 and 123 may be any of various physicalcommunications media for communicating data such as a 56 Kbps line or aT1 line carried over a four-wire shielded cable or over a fiber opticcable.

As used in the foregoing description and the appended claims, a logicalcircuit is defined as a portion of the network circuit wherein data issent over variable communication data paths or logical connectionsestablished between the first and last network devices within a LATA orIEC network and over fixed communication data paths or logicalconnections between LATAs (or between IECs). Thus, no matter what paththe data takes within each LATA or IEC, the beginning and end of eachlogical connection between networks will not change. For example, thelogical circuit of the network circuit in the data network 2 may includea variable communication path within the LATA 5 and a fixedcommunication path (i.e., the logical connection 102) between the LATA 5and the IEC 10. It will be understood by those skilled in the art thatthe logical connections 102 and 104 in the data network 2 may includenetwork-to-network interfaces (“NNIs”) between the last sending switchin a LATA and the first receiving switch in an IEC.

As is known to those skilled in the art, each logical circuit in a datanetwork may be identified by a unique logical identifier. In frame relaynetworks, the logical identifier is called a Data Link ConnectionIdentifier (“DLCI”) while in ATM networks the logical identifier iscalled a Virtual Path Identifier/Virtual Circuit Identifier (“VPI/VCI”).In frame relay networks, the DLCI is a 10-bit address field contained inthe header of each data frame and contains identifying information forthe logical circuit as well as information relating to the destinationof the data in the frame, quality of service (“QoS”) parameters, andother service parameters for handling network congestion. For example,in the data network 2 implemented as a frame relay network, thedesignation DLCI 100 may be used to identify the logical circuit betweenthe host device 112 and the remote device 114. It will be appreciatedthat in data networks in which logical circuit data is communicatedthrough more than one carrier (e.g., an LEC and an IEC) the DLCIdesignation for the logical circuit may change in a specific carrier'snetwork. For example, in the data network 2, the designation DLCI 100may identify the logical circuit in the LATA 5 and LATA 15 but thedesignation DLCI 800 may identify the logical circuit in the IEC 10.

Illustrative QoS parameters which may be included in the DLCI include aVariable Frame Rate (“VFR”) real time parameter and a VFR non-real timeparameter. As is known to those skilled in the art, VFR real time is avariable data rate for frame relay data frames communicated over alogical circuit. Typically, VFR real-time circuits are able to toleratesmall variations in the transmission rate of data (i.e., delay) andsmall losses of frames. Typical applications for VFR real time circuitsmay include, but are not limited to, voice and some types of interactivevideo. VFR non-real time circuits also communicate data frames at avariable data rate but are able to tolerate higher variations in thetransmission rate and thus more delay as these circuits are typically“bursty” (i.e., data is transmitted in short, uneven spurts) in nature.Typical applications for VFR non-real time circuits include, but are notlimited to, inter-LAN communications and Internet traffic.

Other service parameters which may be included in the DLCI include aCommitted Information Rate (“CIR”) parameter and a Committed Burst Size(“Bc”) parameter. As is known to those skilled in the art, the CIRrepresents the average capacity of the logical circuit and the Bcrepresents the maximum amount of data that may be transmitted. It willbe appreciated that the logical circuit may be provisioned such thatwhen the CIR or the Bc is exceeded, the receiving switch in the datanetwork will discard the frame. It should be understood that the logicalcircuit parameters are not limited to CIR and Bc and that otherparameters known to those skilled in the art may also be provisioned,including, but not limited to, Burst Excess Size (“Be”) and CommittedRate Measurement Interval (“Tc”).

In ATM networks, the VPI/VCI is an address field contained in the headerof each ATM data cell and contains identifying information for thelogical circuit as well as information specifying a data cell'sdestination, QoS parameters, and specific bits which may indicate, forexample, the existence of congestion in the network and a threshold fordiscarding cells. Illustrative QoS parameters which may be included inthe VPI/VCI include a Committed Bit Rate (“CBR”) parameter, a VariableBit Rate (“VBR”) parameter, and an Unspecified Bit Rate (“UBR”)parameter. As is known to those skilled in the art, CBR defines aconstant data rate for ATM cells communicated over a logical circuit.Typically, CBR circuits are given the highest priority in a data networkand are very intolerant to delay. Typical applications for CBR circuitsmay include, but are not limited to, video conferencing, voice,television and video-on demand. VBR circuits communicate ATM cells at avariable data rate and are able to tolerate varying degrees of delay.Similar to frame relay variable service parameters, VBR circuits may befurther subdivided into VBR real time and VBR non-real time. VBRnon-real time circuits are able to tolerate more delay. Typicalapplications for ATM VBR circuits may include the same applications asframe relay VFR circuits. UBR circuits communicate ATM cells at anunspecified bit rate and are extremely tolerant to delay. UBR circuitsare typically reserved for non-time sensitive applications such as filetransfer, email, and message and image retrieval.

It should be understood that the logical circuit in the data network 2may be a permanent virtual circuit (“PVC”) available to the network atall times or a temporary or a switched virtual circuit (“SVC”) availableto the network only as long as data is being transmitted. It should beunderstood that the data network 2 may further include additionalswitches or other interconnected network elements (not shown) creatingmultiple paths within each LATA and IEC for defining each PVC or SVC inthe data network. It will be appreciated that the data communicated overthe logical connections 102 and 104 may be physically carried by thephysical connections 106 and 108.

The data network 2 may also include a failover network 17 for reroutinglogical circuit data, according to an embodiment of the invention. Thefailover network 17 may include a network failover circuit includingphysical connections 134 and 144 and logical connections 122 and 132 forrerouting logical circuit data in the event of a failure in the networkcircuit between the host device 112 and the remote device 114. Thefailover network 17 will be described in greater detail in thedescription of FIG. 4 below. The data network 2 may also include anetwork management system 175 in communication with the LATA 5, the LATA15, and the failover network 17. The network management system 175 maybe utilized to obtain status information for the logical and physicalcircuit between the host device 112 and the remote device 114. Thenetwork management system 175 may also be utilized for rerouting logicaldata in the data network 2 between the host device 112 and the remotedevice 114. The network management system 175 will be discussed ingreater detail in the description of FIG. 3 below.

FIG. 2 illustrates the LATA 5 in the data network 2 described in FIG. 1above, according to an embodiment of the present invention. As shown inFIG. 2, the LATA 5 includes interconnected network devices such asswitches 186, 187, and 188. It will be appreciated that the data network2 may also contain other interconnected network devices and elements(not shown) such as digital access and cross connect switches (“DACS”),channel service units (“CSUs”), and data service units (“DSUs”). Asdiscussed above in the description of FIG. 1, the connection data pathsof a logical circuit within a data network may vary between the firstand last network devices in a data network. For example, as shown inFIG. 2, the logical circuit in the LATA 5 may include the communicationpath 185 between the switches 186 and 188 or the communication path 184between the switches 186, 187, and 188. As discussed above, it should beunderstood that the actual path taken by data through the LATA 5 is notfixed and may vary from time to time, such as when automatic reroutingtakes place.

It will be appreciated that the switches 186, 187, and 188 may include asignaling mechanism for monitoring and signaling the status of thelogical circuit in the data network 2. Each time a change in the statusof the logical circuit is detected (e.g., a receiving switch beginsdropping frames), the switch generates an alarm or “trap” which may thenbe communicated to a management station, such as a logical elementmodule (described in detail in the description of FIG. 3 below), in thenetwork management system 175. In one embodiment, the signalingmechanism may be in accord with a Local Management Interface (“LMI”)specification, which provides for the sending and receiving of “statusinquiries” between a data network and a host or remote device. The LMIspecification includes obtaining status information through the use ofspecial management frames (in frame relay networks) or cells (in ATMnetworks). In frame relay networks, for example, the special managementframes monitor the status of logical connections and provide informationregarding the health of the network. In the data network 2, the host andremote devices 112 and 114 receive status information from theindividual LATAs they are connected to in response to a status requestsent in a special management frame or cell. The LMI status informationmay include, for example, whether or not the logical circuit iscongested or whether or not the logical circuit has failed. It should beunderstood that the parameters and the signaling mechanism discussedabove are optional and that other parameters and mechanisms may also beutilized to obtain connection status information for a logical circuit.

FIG. 3 illustrates the network management system 175 which may beutilized to automatically track reroute statistics during the reroutingof logical circuit data in the data network 2 of FIG. 1, according to anembodiment of the invention. The network management system 175 includesa service order system 160, a network database 170, a logical elementmodule 153, a physical element module 155, a network management module176, and a test module 180. The service order system 160 is utilized inthe data network 2 for receiving service orders for provisioning networkcircuits. The service order includes information defining thetransmission characteristics (i.e., the logical circuit) of the networkcircuit. The service order also contains the access speed, CIR, burstrates, and excess burst rates. The service order system 160 communicatesthe service order information to a network database 170 over managementtrunk 172. The network database 170 assigns and stores the parametersfor the physical circuit for the network circuit such as a port numberon the switch 186 for transmitting data over the physical connection 121to and from the host device 112.

The network database 170 may also be in communication with an operationssupport system (not shown) for assigning physical equipment to thenetwork circuit and for maintaining an inventory of the physicalassignments for the network circuit. An illustrative operations supportsystem is “TIRKS”®(Trunks Integrated Records Keeping System) marketed byTELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J. The network database170 may also be in communication with a Work Force Administration andControl system (“WFA/C”) (not shown) used to assign resources (i.e.,technicians) to work on installing the physical circuit.

The network management system 175 also includes the logical elementmodule 153 which is in communication with the switches in the datanetwork 2 through management trunks 183. The logical element module 153runs a network management application program to monitor the operationof logical circuits which includes receiving trap data generated by theswitches with indicate the status of logical connections. The trap datamay be stored in the logical element module 153 for later analysis andreview. The logical element module 153 is also in communication with thenetwork database 170 via management trunks 172 for accessing informationstored in the network database 170 regarding logical circuits, such asthe logical circuit identifier data. The logical circuit identifier datamay include, for example, the DLCI or VPI/VCI header information foreach data frame or cell in the logical circuit including the circuit'sdestination and service parameters. The logical element module 153 mayconsist of terminals (not shown) that display a map-based graphical userinterface (“GUI”) of the logical connections in the data network. Anillustrative logical element module is the NAVISCORE™ system marketed byLUCENT TECHNOLOGIES, Inc. of Murray Hill, N.J.

The network management system 175 further includes the physical elementmodule 155 in communication with the physical connections of the networkcircuit via management trunks (not shown). The physical element module155 runs a network management application program to monitor theoperation and retrieve data regarding the operation of the physicalcircuit. The physical element module 155 is also in communication withthe network database 170 via management trunks 172 for accessinginformation regarding physical circuits, such as line speed. Similar tothe logical element module 153, the physical logical element module 155may also consist of terminals (not shown) that display a map-based GUIof the physical connections in the LATA 5. An illustrative physicalelement module is the Integrated Testing and Analysis System (“INTAS”),marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J., whichprovides flow-through testing and analysis of telephony services.

The physical element module 155 troubleshoots the physical connectionsfor a physical circuit by communicating with test module 180, whichinterfaces with the physical connections via test access point 156. Thetest module 180 obtains the status of the physical circuit bytransmitting “clean” test signals to test access point 156 (shown inFIG. 2) which “loops back” the signals for detection by the test module180. It should be understood that there may multiple test access pointson each of the physical connections for the physical circuit.

The network management system 175 further includes the networkmanagement module 176 which is in communication with the service ordersystem 160, the network database 170, the logical element module 153,and the physical element module 155 through communications channels 172.It should be understood that in one embodiment, the network managementsystem 176 may also be in communication with the LATA 15, the IEC 10,and the failover network 17. The communications channels 172 may be on aLAN. The network management module 176 may consist of terminals (notshown), which may be part of a general-purpose computer system thatdisplays a map-based GUI of the logical connections in data networks.The network management module 175 may communicate with the logicalelement module 153 and the physical element module 155 using a CommonObject Request Broker Architecture (“CORBA”). As is known to thoseskilled in the art, CORBA is an open, vendor-independent architectureand infrastructure which allows different computer applications to worktogether over one or more networks using a basic set of commands andresponses. The network management module 176 may also serve as aninterface for implementing logical operations to provision and maintainnetwork circuits. The logical operations may be implemented as machineinstructions stored locally or as instructions retrieved from thelogical and physical element modules 153 and 155. An illustrative methoddetailing the provisioning and maintenance of network circuits in a datanetwork is presented in U.S. patent application Ser. No. 10/348,592,entitled “Method And System For Provisioning And Maintaining A CircuitIn A Data Network,” filed on Jan. 23, 2003, which is expresslyincorporated herein by reference. An illustrative network managementmodule is the Broadband Network Management System® (“BBNMS”) marketed byTELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J.

The network management module 176 may also serve as an interface withthe logical element module 153 to receive and store trap data indicatingthe status of the logical connections comprising logical circuits in thedata network 2. It will be appreciated that the network managementmodule 176 may further be configured to compile historical statisticsfor logical circuits based on an analysis of stored trap data. Thesehistorical statistics may include, for example, QoS parameters forlogical circuits, number of “hops” contained within a logical circuit,and the utilization of logical circuits (i.e., the extent to whichlogical circuits are being used) in the data network 2. As used in theforegoing description and the appended claims, a “hop” is the journeythat data packets (or cells) make from one network device to anothernetwork device along a logical circuit. For example, in the LATA 5 ofthe data network 2 (FIG. 2), the logical circuit originating from thehost device 112 the communication path 184 includes two hops between theswitches 186, 187, and 188 while the communication path 185 includes onehop between the switches 186 and 188. It will be appreciated thatutilization may be represented as a percentage corresponding to logicalcircuit usage at a given point in time or over a period of time. Forexample, if a logical circuit supports a T-1 data transmission rate(i.e., 1.544 megabits per second) but, on average, is used to support adata transmission rate of 772 kilobits per second), the logical circuitis only 50% utilized. It will be appreciated that logical circuits withutilizations approaching 100% may suffer congestion some percentage ofthe time. This may occur, for example, when the maximum datatransmission rate (e.g., the Committed Burst Size or Bc) for a logicalcircuit is maintained over an extended period of time.

FIG. 4 illustrates an illustrative failover data network for reroutinglogical circuit data, according to one embodiment of the presentinvention. As shown in FIG. 4, the failover network 17 includes an IEC20, a LATA 25, and an IEC 30. The failover network further includes anetwork failover circuit which includes a physical failover circuit anda logical failover circuit. The physical failover circuit includes thephysical connection 134 between the LATA 5 (shown in FIG. 1) and the IEC20, the physical connection 136 between the IEC 20 and the LATA 25, thephysical connection 138 between the LATA 25 and the IEC 30, and thephysical connection 144 between the IEC 30 and the LATA 15 (shown inFIG. 1). Similarly, the logical failover circuit may include the logicalconnection 122 between the LATA 5 (shown in FIG. 1) and the IEC 20, thelogical connection 124 between the IEC 20 and the LATA 25, the logicalconnection 126 between the LATA 25 and the IEC 30, and the logicalconnection 132 between the IEC 30 and the LATA 15 (shown in FIG. 1). Itshould be understood that in one embodiment, the network failovercircuit illustrated in the failover network 17 may include a dedicatedphysical circuit and a dedicated logical circuit provisioned by anetwork service provider serving the LATAs 5, 15, and 25 and the IECs 20and 30, for rerouting logical data from a failed logical circuit.

FIG. 5 is a flowchart describing logical operations 500 performed by thenetwork management system 175 for automatically tracking the reroutingof logical circuit data in a data network, according to an embodiment ofthe invention. It will be appreciated that the logical operations 500may be initiated when data is rerouted from a logical circuit to alogical failover circuit (e.g., a logical failover circuit in thefailover network 17) by the network management module 176. It will beappreciated that the network management module 176 may be configured andutilized to automatically detect logical circuit failures and reroutelogical circuit data from the failed logical circuits in a data network.An illustrative method detailing the automatic monitoring of logicalcircuits to identify a logical circuit failure in a data network ispresented in co-pending U.S. patent application Ser. No. 10/745,170,entitled “Method And System For Automatically Identifying A LogicalCircuit Failure In A Data Network,” filed on Dec. 23, 2003, which isexpressly incorporated herein by reference. An illustrative methoddetailing the rerouting of logical circuit data to a logical failovercircuit is presented in co-pending U.S. patent application Ser. No.10/744,921, entitled “Method And System For Automatically ReroutingLogical Circuit Data In A Data Network,” filed on Dec. 23, 2003, whichis expressly incorporated herein by reference.

The logical operations 500 begin at operation 505 where the networkmanagement module 176 generates current reroute statistics from trapdata received for failed logical circuits being rerouted in the datanetwork 2. As discussed above in the description of FIGS. 2 and 3, trapdata is generated by the switches in the data network 2 and includesstatus information for logical circuits such as the current status of alogical circuit (i.e., whether or not the failed logical circuit hasbeen restored), QoS parameters, current utilization of logical failovercircuits, and other logical circuit service parameters. The trap dataalso includes logical circuit identification information.

In the data network 2, the trap data generated by the switches isgenerated in “real-time” and communicated to the logical element module153 thus are not generally stored by the switches themselves but ratherare communicated to the logical element module 153 via management trunks183 (FIG. 2) where the trap data is kept in a temporary storage buffer.As a result, once the temporary storage buffer is full, old trap data isoverwritten with new trap data. The network management module 176, incommunication with the logical element module 153 via management trunk172 (FIG. 3) is configured to receive and collect the trap data from thelogical element module 153 generated by one or more switches andgenerate “reroute statistics” detailing the status of rerouted logicalcircuit data in the data network 2. The reroute statistics may includethe reroute status of the logical circuit data (i.e., whether the failedlogical circuit has been restored), the logical circuit identificationof the failed logical circuit (i.e., the DLCI or VPI/VCI), the logicalcircuit identification of the logical failover circuit, the number ofhops taken by the logical failover circuit, the utilization of thelogical failover circuit, and the QoS parameters of the logical failovercircuit.

As discussed briefly above, the network management module 176 may beconfigured to automatically reroute logical circuit data from a failedlogical circuit to a logical failover circuit in the data network 2.During the reroute of logical circuit data, the network managementmodule 176 may also be configured to rename the logical circuitidentifier assigned to a failed logical circuit to the logical circuitidentifier assigned to a corresponding logical failover circuit untilthe failed logical circuit has been restored. An illustrative methoddetailing the renaming the renaming of logical circuit identifiers ispresented in co-pending U.S. patent application Ser. No. 10/745,047,entitled “Method And System For Automatically Renaming Logical CircuitIdentifiers For Rerouted Logical Circuits In A Data Network,” filed onDec. 23, 2003, which is expressly incorporated herein by reference.

The logical operations 500 continue from operation 505 to operation 510where the network management module 176 generates a table for presentingthe current reroute statistics generated at operation 505. It will beappreciated that the table may be presented in an electronic format sothat it is graphically displayed on one or more display terminals of thenetwork management module 176. FIG. 6 is a table presenting currentreroute statistics which may be generated for rerouted logical circuitsin the data network 2, according to an embodiment of the invention. Thetable will be discussed in greater detail in the description of FIG. 6below.

The logical operations 500 then continue from operation 510 to operation515 where the network management module 176 receives updated trap datafor currently rerouted logical circuits from the logical element module153. The updated trap data may include, for example, information that apreviously failed logical circuit is successfully communicating data inthe data network 2. The logical operations 500 then continue fromoperation 515 to operation 520 where the network management module 176requests updated trap data. The updated trap data may indicate, forexample, that one or more logical circuits have been restored in thedata network 2. If no updated trap data is available, then the logicaloperations 500 return to operation 515 where the network managementmodule 176 waits to receive further updated trap data. If, however,updated trap data is available to be received by the network managementmodule 176, then the logical operations 500 continue from operation 520to operation 525.

At operation 525, the network management module 176 generates updatedreroute statistics based on the received updated trap data and thenupdates the table (generated at operation 510) at operation 530. FIG. 7is a table presenting updated reroute statistics which may be generatedfor rerouted logical circuits in the data network 2, according to anembodiment of the invention. The table will be discussed in greaterdetail in the description of FIG. 7 below. The logical operations 500then continue at operation 535.

At operation 535, the network management module 176 generates billingdata based on the time period logical circuit data was rerouted to alogical failover circuit in the data network 2. It will be appreciatedthat the network management module 176 may be configured to record thetime period logical circuit data from failed logical circuits arererouted in a data network. Once the failed logical circuit is restored,the network management module may generate a bill for an affectedcustomer based on the time the logical circuit data was rerouted. Thelogical operations 500 then end.

FIG. 6A is a table 190 presenting current reroute statistics which maybe generated by the network management module 176 for rerouted logicalcircuits in the data network 2, according to an embodiment of theinvention. As shown in FIG. 6, the table includes a LOGICAL CIRCUIT IDcolumn 52, a REROUTE STATUS column 54, a LOGICAL FAILOVER CIRCUIT IDcolumn 56, a # HOPS column 58, a UTILIZATION column 60, a QUALITY OFSERVICE (QoS) column 62, and a REROUTE PERIOD column 64. The LOGICALCIRCUIT ID column 52 lists the logical circuit IDs for logical circuitsbelonging to one or more network circuit customers in the data network2. The REROUTE STATUS column 54 lists whether or not each of the logicalcircuits in the LOGICAL CIRCUIT ID column 52 is currently beingrerouted. The LOGICAL FAILOVER CIRCUIT ID column 56 lists the logicalcircuit IDs for logical failover circuits which may be utilized forrerouting data from the logical circuits listed in the LOGICAL CIRCUITID column 52. The # HOPS column 58 lists the number of hops taken bydata being communicated through the logical failover circuits identifiedin the LOGICAL FAILOVER CIRCUIT ID column 56. The UTILIZATION column 60lists the utilization percentage of the logical failover circuitsidentified in the LOGICAL FAILOVER CIRCUIT ID column 56 by reroutedlogical circuit data. The QoS column 62 lists the quality of serviceoffered for rerouted data by each of the logical failover circuitsidentified in the LOGICAL FAILOVER CIRCUIT ID column 56. The REROUTEPERIOD column 64 lists the amount of time the data from each of thelogical circuits identified in the LOGICAL CIRCUIT ID column 52 has beenrerouted to the logical failover circuits identified in the LOGICALFAILOVER CIRCUIT ID column 56.

For example, the table 190 indicates in row 66 that the logical circuitidentified as 101 is currently being rerouted to a logical failovercircuit identified as 901, that the logical failover circuit includesfour hops, that the logical failover circuit is 95% utilized, thatlogical failover circuit has a QoS of UBR, and that the data has beenrerouted for two hours in the data network. It will be appreciated thatthe reroute statistics listed in the table 190 may be used by a networkcircuit provider to improve the management of rerouted logical circuitdata in a data network. For example, a technician may notice that thelogical failover circuit 901 is 95% utilized and thus subject tocongestion (i.e., lost data packets or cells). As a result, thetechnician may initiate a subsequent reroute of the logical circuit datato another available failover logical circuit to minimize thepossibility of customer data loss.

FIG. 6B is a table 190 presenting updated reroute statistics which maybe generated by the network management module 176 for rerouted logicalcircuits in the data network 2, according to an embodiment of theinvention. As shown in the table 190, the updated reroute statisticsindicate that the data communicated by logical circuit IDs 101 and 102are no longer being rerouted, and that the reroute period for eachcircuit was three hours and five hours, respectively at a QoS of UBR. Itwill be appreciated that a network circuit customer may use the updatedreroute statistics in the table 190 to more effectively manage logicalcircuit rerouting in the data network. For example, if the logicalcircuit identified as 101 is normally at a CBR QoS, a customer may notdesire to have high quality logical circuit data (such as videoconferencing data) rerouted to the lower quality UBR logical failovercircuit 901 if the logical circuit 101 fails. Since high quality data(such as video conferencing data) is typically intolerant to the delayinherent in UBR circuits, the customer may direct the network circuitprovider to reroute data from the logical circuit 101 only to CBR or VBRlogical failover circuits (if available).

It will be appreciated that the embodiments of the invention describedabove provide for a method and system for automatically tracking thererouting of logical circuit data in a data network. The variousembodiments described above are provided by way of illustration only andshould not be construed to limit the invention. Those skilled in the artwill readily recognize various modifications and changes that may bemade to the present invention without following the example embodimentsand applications illustrated and described herein, and without departingfrom the true spirit and scope of the present invention, which is setforth in the following claims.

1. A method of rerouting data in a data network, the method comprising:updating reroute information in response to a dropped packet associatedwith a quality of service parameter having been exceeded; and reroutingtransmitted data to at least one logical failover circuit in the datanetwork from at least one failed logical circuit associated with theexceeded quality of service parameter, wherein the at least one logicalfailover circuit is selected based on a bit rate capability specified tobe one of a committed bit rate, a variable bit rate, or an unspecifiedbit rate.
 2. A method as defined in claim 1, wherein updating thereroute information comprises updating the reroute information in atable without manual intervention.
 3. A method as defined in claim 2,further comprising storing in the table second information indicatingthe duration for which the transmitted data was rerouted to the at leastone logical failover circuit.
 4. A method as defined in claim 1, furthercomprising generating a billing report including the rerouteinformation.
 5. A method as defined in claim 1, wherein updating thereroute information in response to the dropped packet associated withthe quality of service parameter having been exceeded comprisesreceiving trap data generated by switches in substantially real-time,wherein the trap data is indicative of the dropped packet associatedwith the exceeded quality of service parameter.
 6. A method as definedin claim 5, wherein the trap data includes a logical identifier for eachof the at least one failed logical circuit and a second logicalidentifier for the at least one logical failover circuit.
 7. A method asdefined in claim 1, further comprising renaming a first logical circuitidentifier assigned to the at least one failed logical circuit to asecond logical circuit identifier assigned to the at least one logicalfailover circuit until the failed logical circuit is restored.
 8. Amethod as defined in claim 1, wherein the quality of service parameteris one of a committed information rate or a committed burst size.
 9. Asystem to reroute data in a data network, the system comprising: anetwork management module configured to: update reroute information inresponse to a dropped packet associated with a quality of serviceparameter having been exceeded; and reroute transmitted data to at leastone logical failover circuit in the data network from at least onefailed logical circuit associated with the exceeded quality of serviceparameter, wherein the at least one logical failover circuit is selectedbased on a bit rate capability specified to be one of a committed bitrate, a variable bit rate, or an unspecified bit rate.
 10. A system asdefined in claim 1, wherein the network management module is configuredto update the reroute information in a table without manualintervention.
 11. A system as defined in claim 10, wherein the networkmanagement module is further configured to store in the table secondinformation indicating the duration for which the transmitted data wasrerouted to the at least one logical failover circuit.
 12. A system asdefined in claim 9, wherein the network management module is furtherconfigured to generate a billing report including the rerouteinformation.
 13. A system as defined in claim 9, wherein the networkmanagement module is configured to update the reroute information basedon trap data generated by switches in substantially real-time, whereinthe trap data is indicative of the dropped packet associated with theexceeded quality of service parameter.
 14. A system as defined in claim13, wherein the trap data includes a first logical identifier for eachof the at least one failed logical circuit and a second logicalidentifier for the at least one logical failover circuit.
 15. A systemas defined in claim 9, wherein the network management module is furtherconfigured to rename a first logical circuit identifier assigned to theat least one failed logical circuit to a second logical circuitidentifier assigned to the at least one logical failover circuit untilthe failed logical circuit is restored.
 16. A system as defined in claim9, wherein the quality of service parameter is one of a committedinformation rate or a committed burst size.
 17. A machine accessiblemedium having instructions stored thereon that, when executed, cause amachine to: update reroute information in response to a dropped packetassociated with a quality of service parameter having been exceeded; andreroute transmitted data to at least one logical failover circuit in thedata network from at least one failed logical circuit associated withthe exceeded quality of service parameter, wherein the at least onelogical failover circuit is selected based on a bit rate capabilityspecified to be one of a committed bit rate, a variable bit rate, or anunspecified bit rate.
 18. A machine accessible medium as defined inclaim 17 having instructions stored thereon that, when executed, causethe machine to update the reroute information in a table without manualintervention.
 19. A machine accessible medium as defined in claim 18having instructions stored thereon that, when executed, cause themachine to store in the table second information indicating the durationfor which the transmitted data was rerouted to the at least one logicalfailover circuit.
 20. A machine accessible medium as defined in claim 17having instructions stored thereon that, when executed, cause themachine to generate a billing report including the reroute information.21. A machine accessible medium as defined in claim 17 havinginstructions stored thereon that, when executed, cause the machine toupdate the reroute information based on receiving trap data generated byswitches in substantially real-time, wherein the trap data is indicativeof the dropped packet associated with the exceeded quality of serviceparameter.
 22. A machine accessible medium as defined in claim 21,wherein the trap data includes a first logical identifier for the atleast one failed logical circuit and a second logical identifier for theat least one logical failover circuit.
 23. A machine accessible mediumas defined in claim 17 having instructions stored thereon that, whenexecuted, cause the machine to rename a first logical circuit identifierassigned to the at least one failed logical circuit to a second logicalcircuit identifier assigned to the at least one logical failover circuituntil the failed logical circuit is restored.
 24. A machine accessiblemedium as defined in claim 17, wherein the quality of service parameteris one of a committed information rate or a committed burst size.